1. Field of the Invention
The present invention relates to a composition for dyeing fibers, especially keratin fibers, containing 1,3-bis-(dicyanomethylen)indane dyestuffs. The keratin fibers include wool, fur and human hair.
2. Prior Art
Two dyeing methods are generally employed for dyeing keratin-containing fibers. In the first method the color of the dyed keratin-containing fibers is produced with a so-called oxidative or permanent dye composition using a mixture of different coupler substances and developer substances and an oxidizing agent. Direct-dyeing (non-oxidative) dye compounds are added, as required, for rounding out the color properties or for producing special color effects. The second method involves the exclusive direct-dyeing dye compounds that are applied to the fibers in a suitable dye carrier. This method is simple to use, mild and characterized by minimal damage to the hair. The direct-dyeing dye compounds used in this latter method have a number of requirements. They must be toxicologically and dermatologically unobjectable and allow the production of colors in the desired intensity, which, among other things, presupposes sufficient water-solubility. Moreover good light-fastness, acid-fastness and friction- or rubbing-fastness is required.
Usually a combination of direct-dyeing (non-oxidative) dye compounds is required for keratin fibers. Since the selection of red-dyeing and blue-dyeing dye compounds that can be used in dye composition for keratin fibers, especially human hair, is limited, it has been necessary to expand the usable color palette.